/Engine/Source/Runtime/Engine/Public/GPUSkinVertexFactory.h
The return value is guaranteed to be greater than zero, but note that it may be higher than the maximum supported bone influences.
static int32 GetBoneInfluenceLimitForAsset ( int32 AssetProvidedLimit, const [ITargetPlatform](API\Developer\TargetPlatform\Interfaces\ITargetPlatform) * TargetPlatform )